1. Field of the Invention
This invention is directed to an improved process and system for the production of hydrogen-rich gas by the steam reforming of hydrocarbons by indirect heat exchange. The device used herein is similar to a shell and tube heat exchanger but the tubes or the shell are filled with reforming catalyst. In this invention, the device is called a "convective reformer". Additionally, this invention addresses the use of the "convective reformer" in unique low energy processing configuration for the manufacture of hydrogen-rich synthesis gas for the production of ammonia, methanol, hydrogen, oxo synthesis gas, reducing gas for the reduction of iron ore, and other processes, in a most thermally efficient manner.
2. Description of the Prior Art
A number of processes have been described in which hot effluent streams emanating from the process are used to provide convection heating to a portion of the process.
Wadsworth, U.S. Pat. No. 1,692,476 discloses a method and apparatus for cracking and rectifying pertroleum oils in which hot effluent is used to preheat the charge.
Wolf, U.S. Pat. No. 1,742,888 discloses a process for converting hydrocarbons and mineral oils in which the hot effluent from a heating furnace is used to preheat entering oil.
Podbielniak, U.S. Pat. No. 2,123,799 discloses a process for the of heat treatment of hydrocarbon gases in which effluent from a conversion furnace preheats an incoming gas charge.
Berg et al., U.S. Pat. No. 2,809,922 discloses a catalytic conversion process and apparatus having improved temperature control of the reaction and which makes extensive use of heat interchange between different portions of the apparatus.
Vorum, U.S. Pat. No. 3,278,452 discloses a method of producing hydrogen-containing gases in which steam for reforming and natural gas for reacting are formed and heated in the convective portion of a primary reformer before being passed to a secondary reformer.
Marshall, Jr., U.S. Pat. No. 3,367,882 discloses an ammonia synthesis gas process in which the hydrogen gas feed is preheated by convection means from reformer heat before passing into the primary reformer. Waste heat boilers make use of the hot effluents in the system to generate process steam.
Wirth et al., U.S. Pat. No. 3,661,767 discloses a fluid coking-steam cracking combination process wherein heavy and light fractions pass from respective sections of the coker vessel through the convection section of the steam cracker, before being returned to the coker or removed as product.
Dougherty, U.S. Pat. No. 3,705,009 discloses heat recycling for ammonia preparation in which process natural gas passes through a convective preheater portion of a primary reformer apparatus. This portion is also used to heat process air for the secondary reformer. Waste heat boilers are used to recover heat from the reformer effluents.
Bacsik, U.S. Pat. No. 4,321,130 discloses the preheating of feed gas in the convection portion of a pyrolysis furnace tubular reactor before passing to a primary fractionator, and the use of fractionator effluent to preheat combustion air by employing a bottom pump around, top pump around and/or quench water streams.
Crawford et al., U.S. Pat. No. 4,162,290 discloses a process for reforming hydrocarbons into hydrogen and ammonia, in which a convective reformer is used in parallel with a primary reformer and sensible heat from a secondary reformer effluent is used as the heat source for the convective reforming section.